This invention relates to both single and double hung window systems. Single hung window systems have only a single sash and double hung windows have two sashes, each of which are inserted into jamb channels to enable the vertical movement of the sashes in the window system. A locking pivot facilitates the cleaning and/or removal of each sash by allowing the sash to be tilted with respect to the window frame. Carriers are used to control the vertical movement of the sash throughout the jamb channel and facilitate the pivoting of the sash by lockingly engaging the sash to the jamb channel as the sash is pivoted. The pivot means can be a cylindrical rod or guide pin that inserts into the opening of a rotatable cam located in the carrier. As the cam rotates, it urges locking members forcibly against the walls of the jamb channel to secure the carrier and thus the sash in place.
The initial assembly of pivotable windows can be complex. Additionally, in order to replace an aged, broken or malfunctioning carrier or balance, a portion of the jamb channel often must be deformed or entirely removed and replaced to gain access to the defective part. Also, since conventional balance systems consist of an integral balance/carrier assembly, the entire assembly must be replaced even though only one element may be defective. It is desirable, therefore, to provide a carrier and balance system that will facilitate the initial assembly of the window, permit easier removal and replacement of defective parts of the sash balance system once the window has been installed in the wall of a building and allow the replacement of only the defective part rather than the entire carrier and balance assembly.